Radio tuning device



May 23, 195o L, M, TEMPLE 2,509,193

RADIO TUNING DEVICE 37 n 4/ .In 39A f wir,

May 23, 1950 M. TEMPLE 2,509,193

RADIO TUNING DEVICE Filed May 8, 1945 2 4Sl'x'ehS-Sheet 2 wwf/Vm? Mm M. Tfn/@M ber I3 of aluminum or like material.

Patented May 23, 1950 RADIO TUNING DEVICE Lemuel M. Temple, Scarsdale, N. Y., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application May 8, 1948, Serial No. 668,207

2 Claims.

This invention relates to radio tuning devices and more particularly to the use of such devices in connection with sub-miniature radio receivers.

It is an object of this invention to provide a compact unitary tuning device in combination with a rectilinear drive for same.

The above and other objects are generally attained by the use of a rectilinear drive of novel construction in combination with a permeability tuning device to provide a straight-line structure. When speaking of a straight-line structure, the use of the term connotes the arrangement of components in substantially linear sequence as distinguished from the usual angular placement of, for example, tunable elements which are placed at right angles to their usual means of support. The use of such novel construction allows the placement of components, such as vacuum tubes, resistors, condensers and power supply, well within the framework of such a structure and provides, despite the apparent crowding of components, a highly efficient radio receiver of a size approximately that of a commercial package of cigarettes. The invention will be better understood from the following description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a perspective view of one embodiment of the invention used in conjunction with a permeability tuning device lwith certain parts broken way to show constructional details;

Fig. 2 is a partial cross-sectional view along line 2-2 of Fig. 1;

Fig. 3 is a top view of the device shown in Fig. 1, partly broken away to show the indicating and indicator magnifying means; and

Fig. 4 is a view of the device showing, generally, the placement of various components of a radio receiver.

Referring now more particularly to Fig. 1, a rectangular plastic member I supports a magnifying lens II. When speaking of plastics in this specication, theA term is used to denote dielectric or insulating material. Below member III and spaced therefrom by a plurality of metal spaced bushings I2 is a. second rectangular mem- Fastened to said member I3 is a disk-like metal member I4, the edge of which is knurled or milled, the milling I5 being parallel with the axis of the disk member I4. Actually, the edge of said disk I4 is milled in a manner similar to a coin. As set forth in more detail in Fig. 2, the milled disk I4 is fastened to member I3 with a bolt I6 and nut II but is free to rotate. Other means of fastening the disk may be used, such as riveting, or bolt I6 may be threadedly engaged with member I3. Disk I4 has inscribed on the upper surface and outer edge a series of numerals I8, as illustrated in Fig. 3 to indicate the received radio frequency. As disk I4 is rotated, said numerals will appear under the magnifying lens I I, considerably enlarged, as indicated by reference numeral I 9.

Positioned between members I3 and 2|, said member 2I being made 0f material similar to that used for member I3, is a rectilinear device consisting of a lead screw 22, a movable supportlng member 23 of aluminum or the like, substantially rectangular in form, said movable support being threadedly engaged with said lead screw, and an anti-backlash arrangement comprising a flat rectangular metal member 24' threadedly engaged with said lead screw in part and rigidly aixed to a guide rod 25 in part. Attachment of said guide rod 25 is achieved by providing an aperture 26 in said member 24, and then cutting a slit 21 from the shorter side of said member 24 extending to said aperture. The upper part 25 of rod 25 is passed through said aperture 26 and that portion of member 24 in the vicinity of slit 2'I is drawn together to firmly grasp rod 25. Disposed between members 23 and 24 is a helical metal spring 2B, said spring being coiled around the lead screw 22. As stated before, both members 23 and 24' are threadedly engaged with said lead screw. By rotating member 24 in a direction toward member 23 until the desired tension is acquired, and then inserting rod 25 in the aperture 26 and crimping member 24 as heretofore explained, a pressure is exerted in two directions against the threads of the lead screw 22 and backlash or play is eliminated when said lead screw is rotated. In order to avoid misalignment of member 24 with respect to lead screw 22, as by tilting upwardly of said member 24, rod 25 is made smaller in diameter at that portion which extends above member 23 and a reinforcing metal member 29 is attached, by sweating or other known means, to said member 23. The dissimilar diameters of rod 25 form a shoulder 30 which abuts the underside of member 29 and prevents the rod 25 from slipping upwardly under the tension exerted by spring member 28.

That portion 3| of lead screw 22 extending above member I3 is milled as at 32 so as to engage the milling or knurling on disk I4. This feature is more clearly indicated in Fi-g. 2. The milling covers enough of the length of said portion 3| to engage said disk, and the portion 33 above the milling 32 is used to support a plastic knob 34 for manipulation, by hand, of said lead screw. In addition the diameter of portion 3| of lead screw 22 is substantially smaller, so that a shoulder 35 is formed at the junction of the dissimilar diameters, said shoulder abutting the underside of member I3. Similarly a shoulder 36 is provided at the opposite end of lead screw 22 which abuts the upper side of member 2|. By properly adjusting spacing rods 31, the distance between members I3 and 2| is such that lead screw 22 is kept in proper position and can be freely rotated.

Attached to the movable member 23 is a plurality of permeability tuning cores 38, each of said cores being aflixed to said member 23 by a bolt 39 imbedded in said core 38 and extending through member 23 where said bolt 39 is held in position by a, nut 4'0. However, provision is made to adjust said core with respect to its distance from members 23 by rotating nut 40. A spring member 4| maintains this distance between member 23 and core 38 because of the tension exerted by said spring 4| therebetween. Spring 4| surrounds bolt 39 and is disposed between member 23 and the top of core 38.

To prevent member 23 from turning as lead screw 22 is rotated, a rod-like member 42 is provided which is rigidly affixed between members |3 and 2|. Member 25 being rigidly affixed to the movable members 23 and 24 and having a slidable t within a metal tubular member 43 also aids in maintaining alignment of the movable structure. Rod 25A serves a similar function as rod 25 and has a slidable fit within a metal tubular member 44. In addition rod 25A is provided with a pair of locking nuts 45, only one of which is visible in Fig. 1, disposed either side of member 23, said nuts being used to lock rod 25A in position so that it acts as a stop for the movable member 23 in an upward direction.

Positioned between member 2| and a third rectangular metal member 45, preferably made of aluminum, are a plurality of elongated metal bushings 41. These bushings are threaded internally to receive at the lower end thereof bolts 48 which are used to fasten member 46 against the lower plane surface of bushing 41. At the opposite or upper end of said bushings, the rods 31 are threadedly engaged with the internally threaded bushings 41, as illustrated by reference numeral 49, which shows a cross-sectional view of this particular arrangement. The nuts 50 are a means of adjusting the distance between members I3 and 2| and for clamping the bushings tightly between members 2| and 46.

The purpose of member 46 is to hold in position a plurality of shielded inductors or solenoids between itself and member 2|. These solenoids are held in proper alignment so that cores 38 may readily slide in and out of a hollow space, provided for this purpose, within said solenoids.

Fig. 4 shows a collinear arrangement wherein the various components, which are part of a radio receiver, may be assembled. The View of the device has been enlarged several times to bring out in better detail said arrangement of parts. In this particular embodiment four subminiature vacuum tubes 52, 53, 54 and 55 are mounted, in a socket strip 56, parallel to the tuning cores 38 and are well within the dimensions of the structure. Between members 2| and 46 and against the solenoids 5| is placed a substantially thin insulating member 51. Upon this member are supported a plurality of condensers 58, 59, 60 and 6| and a plurality of resistors 62, 63, 64 and 65. Advantage is also taken of the space between members 2| and 46 along the lefthand edge of the structure for the placement of condensers 66 and 61. Connecting terminal points 68 are provided on said member 51 for electrical connections between the solenoids, condensers, resistors, and other circuit points, thus providing for short leads between components and simplifying wiring and assembly of the entire structure. A variable resistor or volume control 69 is mounted on member l0 adjacent the tuning knob 34, thus providing for convenient manipulation of the device when receiving broadcast signals. Batteries 10, 1| and 12 for supplying filament and plate potentials to the vacuum tubes above are positioned below the inductors 5|. An insulating strip 13 supports the spring contacts 14 only one of which is visible in the drawing. Said strip also insulates the structure from said batteries. The novel features embodied in this device are represented by the combination of a novel rectilinear drive in combination with a tunable assembly. It is this arrangement of a straight-line structure as distinguished from the usual angular placement of components that provides a device having dimensions such that, when completely assembly can be readily placed in a vest pocket and just as readily tuned and manipulated from this aforesaid position. Means for attaching an earphone and antenna to the device are not indicated but such means can be attached to the device very conveniently by one skilled in the art. As pointed out in the foregoing description and the attached drawings, the novel arrangement and cooperation of various parts of the device provide a structure which can be quickly assembled and such parts as members I0, i3, 2|, 23 and 46 can be stamped out for added economy. The spacing rods 31 and bushings 41 are of regular stock size. The use of milled or knurled surfaces to provide geared engagement of the lead screw 22 with the indicating disk i4 represents a very definite economy in manufacturing the device. In addition the simple but novel means for preventing lost motion between the indicator disk |4 and the cores 38, comprising members 24, 25 and 28, is an important contribution to accuracy of tuning not usually provided for in commercially constructed radio receivers.

Having described and illustrated the invention, it is of course understood that many modifications and alterations may be made without departing from the spirit and scope of the invention.

What is claimed is:

l. In combination with a radio tuning device, radio tuning means, a rectilinear drive comprising, a plurality of parallel supporting members, rotatable means disposed between a first and a second of said supporting members, movable supporting means threadedly engaged with said rotatable means, tensioning means consisting of a flat member threadedly engaged, in part, with said rotatable means and rigidly affixed in part to said movable supporting means, a spring member disposed between said fiat member and movable supporting means, said spring member surrounding said rotatable means, whereby tension between said rotatable means and movable supporting means prevent backlash therebetween, and means for attaching said tuning means to said movable supporting means, whereby manipulation of said rotatable means will impart linear motion to said radio tuning means.

2. 1n combination with a radio Vtuning device, radio tuning means, a rectilinear drive comprising, a plurality of parallel supporting members, rotatable means disposed between a rst and a second of said supporting members, movable supporting means having at least one aperture therein, said supporting means being threadedly engaged with said rotatable means, means for attaching at least one permeability tuning means to said movable supporting means consisting of a threaded rod aiiixed to said tuning means at one end thereof, said rod having a diameter substantially smaller than said tuning means and extending through an aperture in said movable supporting means, means for retaining said rod within said aperture, and a spring member disposed between said movable support and a shoulder formed at the junction of said tuning means and rod, whereby tension exerted by said member maintains a predetermined distance therebetween, whereby manipulation of said rotatable means will impart linear motion to said radio tuning means.

LEMUEL M. TEMPLE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 155,862 Crenshaw Oct. 13, 1874 1,219,452 Gilbert Mar. 10, 1917 1,566,069 Buchholz et al. Dec. 15, 1925 1,840,215 Sordilio Jan. 5, 1932 1,965,303 Weber July 3, 1934 2,199,555 Andrews May '7, 1940 2,206,512 Reinholz et al. July 2, 1940 2,252,796 Whittell Aug. 19, 1941 2,260,985 Benton et al. Oct. 28, i941 2,338,134 Sands et al. Jan. 4, 1944 2,424,506 Sands July 22, 194'? 

